Lens configuration for a thermally compensated chromatic confocal point sensor

摘要

A chromatically dispersive lens configuration including thermal compensation may be utilized in chromatic confocal point sensor optical pens for chromatic range sensing. The lens configuration may include a negative power doublet lens and a positive power lens portion. The positive power lens portion comprises at least two lens elements which compensate for the overall thermal sensitivity of a chromatic confocal point sensor optical pen. The lens elements of the positive power lens portion which compensate for thermal sensitivity have an average coefficient of thermal defocus which is in a range that is at lowest 10 ppm per 10° C. The lens configuration can be implemented with dimensions which fit a standard commercial chromatic confocal point sensor optical pen, while maintaining a level of optical performance sufficient for chromatic range sensing.